Stapling device with selective cutting

ABSTRACT

A surgical stapling device includes a drive assembly and a knife bar assembly that can be selectively coupled together or uncoupled from each other to place the stapling device in a cutting mode or in a non-cutting mode. The stapling device may also include a locking member that locks a distal portion of the anvil to a distal portion of the cartridge assembly to define a maximum tissue gap between the anvil and the cartridge assembly.

FIELD

This disclosure is directed to a surgical stapling device and, more particularly, to a linear surgical stapling device having a tool assembly that can selectively be operated in a cutting mode or a non-cutting mode.

BACKGROUND

Surgical stapling devices are commonly used during a variety of surgical procedures to staple and/or cut tissue. Stapling and cutting of tissue can be accomplished more quickly using surgical stapling devices than can be accomplished using traditional suturing techniques. In addition, endoscopic stapling devices can be used to perform less invasive surgical procedures than possible using traditional suturing techniques. As such, the use of surgical stapling devices to perform certain surgical procedures to reduce patient trauma and improve patient recovery times is desirable.

Typically, linear endoscopic surgical stapling devices include a tool assembly that includes a staple cartridge and an anvil assembly that are movable in relation to each other between open and clamped positions. The staple cartridge defines a plurality of staple pockets that receive staples and the anvil assembly defines a plurality of staple deforming pockets. When the tool assembly is in the clamped position, the staple deforming pockets of the anvil assembly are aligned with the staple pockets of the staple cartridge such that legs of the staples are received and deformed within the staple deforming pockets when the stapling device is fired. The staple cartridge and the anvil assembly must be properly aligned to effect proper staple formation.

Generally, the staple cartridge and the anvil assembly have proximal ends that are secured to each other by a pivot member such that the staple cartridge and the anvil assembly can be pivoted from the open position in which distal ends of the staple cartridge and the anvil assembly are spaced from each other to the clamped position in which the staple cartridge and the anvil assembly are in juxtaposed alignment. During firing of the staples from the staple cartridge, forces on the staple cartridge and the anvil assembly for firing the staples tend to deflect the staple cartridge and anvil assembly outwardly away from each other. In certain stapling devices, a knife bar is provided that includes upper and lower beams that engage the anvil assembly and staple cartridge to minimize deflection of the anvil and cartridge assemblies during firing. In stapling devices that do not include a knife bar, deflection of the anvil and cartridge assemblies may have a detrimental effect on staple formation.

SUMMARY

One aspect of the disclosure is directed to a tool assembly including an anvil, a cartridge assembly, a drive assembly, and a knife assembly. The anvil defines an anvil channel and a knife slot that communicates with the anvil channel. The cartridge assembly includes a channel member and a staple cartridge. The channel member is configured to receive the staple cartridge and defines a longitudinal slot. The staple cartridge supports a plurality of staples and defines a knife slot that is aligned with the longitudinal slot. The drive assembly includes a resilient beam and a working member having a first beam and a first vertical strut. The vertical strut includes first engagement structure. The knife bar assembly includes a knife bar and a flexible drive member. The knife bar includes a second beam and a second vertical strut that supports a knife and includes second engagement structure that is adapted to be coupled to the first engagement structure to couple the drive assembly to the knife bar assembly such that movement of the drive assembly in relation to the anvil and cartridge assembly causes corresponding movement of the knife bar assembly in relation to the anvil and cartridge assembly. The knife bar assembly is rotatable between a first position in which the first and second engagement structures are coupled together and a second position in which the first and second engagement structures are uncoupled.

In embodiments, one of the anvil and the cartridge assembly includes a distal portion having a locking member that is configured to engage the other of the anvil and cartridge assembly to secure the distal portions of the anvil and cartridge assembly together and define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.

In some embodiments, the locking member includes a hook portion that is supported on the distal portion of the anvil and the staple cartridge defines an opening that receives the hook portion when the tool assembly is moved to a clamped position to secure the distal portion of the anvil to the distal portion of the cartridge assembly.

In certain embodiments, the second beam is received with the anvil channel and the second vertical strut extends through the knife slot of the anvil when the knife bar assembly is in the first position and is advanced within the tool assembly.

In embodiments, the first engagement structure includes a first L-shaped slot and the second engagement structure includes a first L-shaped leg, wherein the first L-shaped leg is received within the first L-shaped slot when the knife bar assembly is in the first position.

In some embodiments, the first engagement structure includes a first L-shaped slot and a first L-shaped leg and the second engagement structure includes a second L-shaped leg and a second L-shaped slot, wherein the first L-shaped leg is received within the first L-shaped slot and the second L-shaped leg is received within the second L-shaped slot when the knife bar assembly is in the first position.

Another aspect of the present disclosure is directed to a stapling device including an elongate body and a tool assembly. The elongate body has a proximal portion and a distal portion. The tool assembly is supported on the distal portion of the elongate body and includes an anvil, a cartridge assembly, a drive assembly, and a knife bar assembly. The anvil defines an anvil channel and a knife slot that communicates with the anvil channel. The cartridge assembly includes a channel member and a staple cartridge. The channel member is configured to receive the staple cartridge and defines a longitudinal slot. The staple cartridge supports a plurality of staples and defines a knife slot that is aligned with the longitudinal slot. The drive assembly includes a resilient beam and a working member having a first beam and a first vertical strut. The first vertical strut includes first engagement structure. The knife bar assembly includes a knife bar and a flexible drive member. The knife bar includes a second beam and a second vertical strut. The second vertical strut supports a knife and includes second engagement structure that is adapted to be coupled to the first engagement structure to couple the drive assembly to the knife bar assembly such that movement of the drive assembly in relation to the anvil and cartridge assembly causes corresponding movement of the knife bar assembly in relation to the anvil and cartridge assembly. The knife bar assembly is rotatable between a first position in which the first and second engagement structures are coupled together and a second position in which the first and second engagement structures are uncoupled.

In embodiments, a control knob is supported on the stapling device proximally of the tool assembly. The control knob is secured to the flexible drive member of the knife bar assembly and is rotatable to cause rotation of the knife bar assembly between the first position and the second position.

In some embodiments, the control knob is supported on the elongate body at a location accessible to a clinician.

In certain embodiments, the elongate body includes an inner housing portion that defines a cylindrical cavity that receives the control knob, wherein the control knob does not extend outwardly of an outer diameter of the elongate body.

In embodiments, the control knob includes first and second protrusions and the inner housing portion of the elongate body includes at least one recess positioned to receive the first and second protrusions to retain the control knob in the first and second positions, respectively.

Another aspect of the disclosure is directed to a tool assembly including an anvil, a cartridge assembly, a drive assembly, and a locking member. The anvil defines an anvil channel and a knife slot that communicates with the anvil channel. The cartridge assembly includes a channel member and a staple cartridge. The channel member is configured to receive the staple cartridge and defines a longitudinal slot. The staple cartridge supports a plurality of staples and defines a knife slot that is aligned with the longitudinal slot. The drive assembly includes a resilient beam and a working member having a first beam and a first vertical strut. The first vertical strut includes first engagement structure. The locking member is supported on a distal portion of one of the anvil and the cartridge assembly and is configured to engage the other of the anvil and cartridge assembly to secure the distal portion of the anvil to the distal portion of the cartridge assembly and define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the disclosed surgical stapling device are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective top view of an exemplary embodiment of the disclosed surgical stapling device with a tool assembly of the stapling device in an open condition;

FIG. 2 is a side perspective top view of a reload assembly of the surgical stapling device shown in FIG. 1 with the tool assembly in the open condition;

FIG. 3 is a side perspective bottom view of the tool assembly of the stapling device shown in FIG. 2 from

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG. 2;

FIG. 5 is an enlarged view of the indicated area of detail shown in FIG. 2;

FIG. 6 is a side perspective exploded view of the tool assembly of the reload assembly shown in FIG. 2;

FIG. 7 is an enlarged view of the indicated area of detail shown in FIG. 6;

FIG. 8 is a cross-sectional view taken along section line 8-8 in FIG. 1;

FIG. 9 is a cross-sectional view taken along section line 9-9 of FIG. 8;

FIG. 10 is an enlarged view of the indicated area of detail shown in FIG. 8;

FIG. 11 is a side perspective view of a distal portion of a clamp and knife assembly of the tool assembly shown in FIG. 6 with a knife of the clamp and knife assembly engaged with the clamp of the clamp and knife assembly;

FIG. 12 is a cross-sectional view taken along section line 9-9 of FIG. 8 with as the knife assembly is moved to a position disengaged with the clamp of the clamp and knife assembly;

FIG. 13 is a side perspective view of the distal portion of the clamp and knife assembly of the tool assembly shown in FIG. 6 with the knife of the clamp and knife assembly disengaged from the clamp of the clamp and knife assembly;

FIG. 14 is a side cross-sectional view of the distal portion of the reload assembly shown in FIG. 2 with the knife of the clamp and knife assembly disengaged from the clamp of the clamp and knife assembly;

FIG. 15 is an enlarged view of the indicated area of detail shown in FIG. 14;

FIG. 16 is a cross-sectional view of a distal portion of the tool assembly of the stapling device shown in FIG. 1 as the tool assembly is moved to the clamped position;

FIG. 17 is a cross-sectional view of the tool assembly of the surgical stapling device shown in FIG. 1 with the tool assembly in a clamped position as the clamp member begins to move from a retracted position towards an advanced position disengaged with the knife assembly;

FIG. 18 is an enlarged view of the indicated area of detail shown in FIG. 17;

FIG. 19 is an enlarged view of the indicated area of detail shown in FIG. 17;

FIG. 20 is a cross-sectional view of the distal portion of the tool assembly of the stapling device shown in FIG. 1 as the clamp member is moved to its advanced position with the tool assembly in the clamped position;

FIG. 21 is a cross-sectional view of the distal portion of the tool assembly of the stapling device shown in FIG. 1 with the clamp member in its advanced position and the tool assembly unlocked as the tool assembly moves towards the open position;

FIG. 22 is a cross-sectional view of the tool assembly of the surgical stapling device shown in FIG. 1 with the tool assembly in a clamped position as the clamp member begins to move from the retracted position towards the advanced position engaged with the knife assembly;

FIG. 23 is a cross-sectional view of the distal portion of the tool assembly of the stapling device shown in FIG. 1 with the clamp member in its advanced position engaged with the knife assembly and the tool assembly unlocked as the tool assembly moves towards the open position; and

FIG. 24 is a cross-sectional view of the distal portion of the tool assembly of the stapling device shown in FIG. 1 as the clamp member and the knife assembly move the their retracted positions after the tool assembly has been fired.

DETAILED DESCRIPTION OF EMBODIMENTS

The disclosed stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through small diameter incision or cannula. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel.

In FIG. 1, the surgical stapling device is illustrated generally as stapling device 10 and includes a handle assembly 12, an elongate body 14, and a staple reload 16. The elongate body 14 defines a longitudinal axis “X” and includes a proximal portion that is coupled to the handle assembly 12 and a distal portion that supports the staple reload 16. The staple reload 16 includes a proximal body portion 18 and a tool assembly 20 supported on the proximal body portion 18. The proximal body portion 18 is releasably coupled to the distal portion of the elongate body 14. Alternately, the staple reload 16 and the elongate body 14 can be integrally formed such that the tool assembly 20 is fixedly attached to the elongate body 14.

The handle assembly 12 includes a housing 24 that defines a stationary handgrip 26 and supports a movable trigger 28 and a rotation knob 30. The rotation knob 30 is coupled to a distal portion of the housing 24 for rotation and supports the elongate body 14 such that rotation of the rotation knob 30 causes rotation of the elongate body 14 about the longitudinal axis “X”. The movable trigger 28 is supported by the housing 24 and can be pivoted in relation to the stationary handgrip 26 to actuate the tool assembly 20. In embodiments, the rotation knob 30 also supports an articulation knob 34 that can pivot or rotate about an axis perpendicular to the longitudinal axis “X” to articulate the tool assembly 20 from a position aligned with the longitudinal axis “X” to positions misaligned with the longitudinal axis “X”. Although illustrated as being a manually operated handle assembly 12, it is envisioned that the handle assembly 12 may be electrically or pneumatically powered, and may be adapted for use or coupled to a robotic surgical system.

FIGS. 2-7 illustrate the tool assembly 20 which includes an anvil 36 and a cartridge assembly 38. The anvil 36 and the cartridge assembly 38 each include a distal portion and a proximal portion. The proximal portion of the anvil 36 is coupled to the proximal portion of the cartridge assembly 38 by a pivot member 40 such that the tool assembly 20 can pivot between an open position (FIG. 14) in which the distal portions of the anvil 36 and the cartridge assembly 38 are spaced from each other and a clamped position (FIG. 17) in which the anvil 36 and cartridge assembly 38 are in juxtaposed alignment. The distal portion of the anvil 36 supports a flexible locking member 39 that includes a hook portion 39 a which is described in further detail below. The anvil 36 includes a tissue engaging surface that defines a longitudinally extending knife slot 36 a (FIG. 3)

In embodiments, the cartridge assembly 38 includes a channel member 42 that defines a longitudinal slot 42 a (FIG. 3) and a staple cartridge 44 having a tissue contact surface 46 and a knife slot 44 a (FIG. 2) that is aligned with the longitudinal slot 42 a formed in the channel member 42. The staple cartridge 44 defines a plurality of staple pockets 48 and is received within the channel member 42. In some embodiments, the staple cartridge 44 is adapted to be released from the channel member 42 after firing of the stapling device 10 and replaced with a new staple cartridge 44. Each of the staple pockets 48 is configured and dimensioned to receive a staple (not shown). In embodiments, the staple cartridge 44 has a tissue guide portion 50 (FIG. 4) that is angled in a direction away from the anvil 36 in the distal direction.

The cartridge assembly 38 includes the channel member 42, the staple cartridge 44 which is received within the channel member 42, a knife bar assembly 54, a drive assembly 56, and an actuation sled 58. The channel member 42 defines a recess 60 that receives the staple cartridge 44. The staple cartridge 44 supports a plurality of staples 62 and pushers 62 a (FIG. 6). Each of the staples 62 is supported on a respective pusher 62 a within a respective one of the staple pockets 48 (FIG. 4). In embodiments, the staple pockets 48 are aligned in three linear rows that are positioned on each side of the knife slot 44 a. Alternately, the staple cartridge 44 may include one or more rows of staples 64 or other staple pocket configurations. The tissue guide portion 50 of the staple cartridge 44 defines an opening 65 that is positioned to receive the locking member 39 of the anvil 36 when the tool assembly 20 is moved to the clamped position as described in further detail below. The channel member 42 of the cartridge assembly 38 includes an outer surface 66 that defines a recess 68 (FIG. 3) and includes an angled cam surface 68 a positioned at the proximal end of the recess 68. The longitudinal slot 42 a is positioned within the recess 68 and is configured to receive a portion of the knife bar 54.

The drive assembly 56 includes a resilient beam 70 and a working member 72 supported on the distal end portion of the resilient beam 70. In embodiments, the resilient beam can be formed of stacked laminates although other constructions are envisioned. Although not shown, a proximal end portion of the resilient beam 70 includes a coupling member to couple the proximal end portion of the resilient beam 70 to a drive member (not shown) of the stapling device 10. A suitable coupling member is described in U.S. Pat. No. 5,865,361 and is not described in further detail in this application.

The working member 72 includes a vertical strut 74 and a lower beam 76 that extends in a direction transverse to the vertical strut 74. The lower beam 76 is received within the recess 68 defined in the outer surface 66 of the channel member 42 and the vertical strut 74 extends through the longitudinal slot 42 a of the channel member 42 and the knife slot 44 a of the staple cartridge 44. The vertical strut 74 defines engagement structure. In embodiments, the engagement structure includes an L-shaped slot 78 and an L-shaped leg 78 a that is described in further detail below. The vertical strut 74 and the lower beam 76 define a distal surface 80 that is positioned to abut a proximal end of the actuation sled 58 such that advancement of the working member 72 through the tool assembly 20 causes advancement of the actuation sled 58 through the staple cartridge 44 to eject the staples 64 from the staple cartridge 44.

The knife bar assembly 54 includes a knife bar 82 and a flexible drive member 84. The drive member 84 may include stacked laminates although other constructions are envisioned. In embodiments, the drive member 84 may have a rectangular cross-section although other shapes are envisioned, e.g., circular. The knife bar 82 includes a vertical strut 86, and an upper beam 88. The upper beam 88 is received within an anvil channel 90 (FIG. 8) defined in the anvil 36 when the knife bar assembly 54 is advanced through the tool assembly 20. The vertical strut 86 extends through the knife slot 36 a (FIG. 3) in the anvil 36 and through the knife slot 44 a of the staple cartridge 44. The vertical strut 86 of the knife bar 82 defines a knife 86 a and also includes engagement structure adapted to be coupled to the engagement structure of the drive assembly 56. In embodiments, the engagement structure includes an L-shaped slot 92 and an L-shaped leg 92 a. The L-shaped slot 92 of the vertical strut 86 is dimensioned to receive the L-shaped leg 78 a of the strut 74 and the L-shaped leg 92 a of the vertical strut 86 is dimensioned to be received within the L-shaped slot 78 of the vertical strut 74 to couple the knife bar assembly 54 to the drive assembly 56 as described in further detail below.

The actuation sled 58 includes a central guide member 96 that is received within the knife slot 44 a of the staple cartridge 44 and outwardly spaced cam members 98. The cam members 98 are positioned to engage the pushers 62 a of the staple cartridge 44 as the actuation sled 58 is advanced through the staple cartridge 44 to eject the staples 62 from the staple cartridge 44 as is known in the art. The actuation sled 58 includes a distally extending finger 100 that is positioned to engage the flexible locking member 39 of the anvil 36 when the actuation sled 58 is in its advanced position to disengage the locking member 39 from the staple cartridge 44 as described in further detail below.

FIGS. 2, 5, and 6 illustrate a control knob 102 that is provided to rotate the knife bar assembly 54 into and out of engagement with the drive assembly 56. In embodiments, the control knob 102 is fixedly secured to the drive member 84 of the knife bar assembly 54 such that rotation of the control knob 102 causes corresponding rotation of the knife bar assembly 54 about an axis defined by a central axis of the control knob 102. In embodiments, the control knob 102 defines a rectangular bore 106 that receives the drive member 84 of the knife bar assembly 54 (FIG. 9) such that rotation of the control knob 102 causes rotation of the drive bar 84. In embodiments, the control knob 102 includes an outer surface that has an anti-slip configuration, e.g., ribs or knurling, to allow the control knob 102 to be rotated by a clinician with a finger, e.g., thumb or index finger. As shown, the control knob 102 may be positioned on the proximal body portion 18 of the staple reload 16. Alternately, the control knob 102 may be supported on the handle assembly 12.

FIGS. 8 and 9 illustrate the control knob 102 supported on the proximal body portion 18 of the staple reload 16. In embodiments, the proximal body portion 18 of the stapler reload 16 includes an inner housing portion 108 that defines a cylindrical bore 110 dimensioned to receive the control knob 102. The cylindrical bore 110 is positioned to receive the control knob 102 such that outer portion of the control knob 102 is accessible to a clinician. In embodiments, the inner housing portion 108 of the proximal body portion 18 of the stapler reload 16 defines a flat 112 (FIG. 9) and the outer portion of the control knob 102 projects outwardly of the flat 112 and is accessible to a clinician. The flat 112 allows the outer surface of the control knob 102 to remain within the outer diameter (FIG. 9) of the proximal body portion 18 such that the proximal body portion 18 of the stapler reload 16 can be received within a small diameter trocar assembly.

In embodiments, the control knob 102 includes at least one protrusion 116 that is received in a respective recess 118 formed in the inner housing portion 108 of the proximal body portion 18 of the stapler reload 16 to retain the control knob 102 in a rotatably fixed position. As described in further detail below, the control knob 102 is rotatable from a first position (FIG. 11) in which the knife bar assembly 54 is engaged with the drive assembly 56 to a second position (FIG. 13) in which the knife bar assembly 54 is disengaged from the drive assembly 56.

FIGS. 10 and 11 illustrate the control knob 102 in the first position with the knife bar assembly 54 engaged to the drive assembly 56. In the engaged position, the L-shaped leg 78 a of the vertical strut 74 of the drive assembly 56 is received within the L-shaped slot 92 of the vertical strut 86 of the knife bar assembly 54 and the L-shaped leg 92 a of the vertical strut 86 of the knife bar assembly 54 is received within the L-shaped slot 78 of the vertical strut 74 of the drive assembly 56. When the knife bar assembly 54 is engaged with the drive assembly 56, advancement of the drive assembly 56 through the tool assembly 20 via actuation of the handle assembly 12 (FIG. 1) causes advancement of the knife bar assembly 54 through the tool assembly 20. As described above, advancement of the drive assembly 56 through the tool assembly 20 also advanced the actuation sled 58 through the tool assembly 20 to eject staples 62 from the staple cartridge 44.

FIGS. 12 and 13 illustrate movement of the control knob 102 from the first position to the second position to move the knife bar assembly 54 and the drive assembly 56 from the engaged position (FIG. 11) to the disengaged position (FIG. 13). When the control knob 102 is rotated in the direction indicated by arrow “A” in FIG. 12, the drive member 84 of the knife bar assembly 54 is rotated about the rotation axis of the control knob 102 in the direction indicated by arrow “B” (FIG. 13) to cause rotation of the knife bar 82 about the rotation axis of the control knob 102 in the direction indicated by arrow “C” from engagement with the drive assembly 56. It is noted that the knife bar assembly 54 can only be rotated between the engaged and disengaged positions when the knife bar assembly 54 is in a fully retracted position with the vertical strut 86 of the knife bar 82 positioned proximally of the anvil channel 90 of the anvil 36 and of the knife slot 44 a (FIG. 2) of the staple cartridge 44. Once the knife bar 82 is advanced to a position in which the knife bar 82 is engaged with the anvil 36 and the staple cartridge 44, rotation of the knife bar assembly 54 will be prevented.

FIGS. 14 and 15 illustrate the tool assembly 20 in the open position with the knife bar assembly 54 and the drive assembly 56 in a retracted position and the knife bar assembly 54 disengaged from the drive assembly 56. In this position, the lower beam 76 of the working member 72 of the drive assembly 56 is positioned proximally of the proximal end of the channel member 42 of the cartridge assembly 38. In this position, the knife bar 82 can be rotated via the control knob 102 in relation to the drive assembly 56 between the engaged position and the disengaged position.

FIGS. 16-19 illustrate the tool assembly 20 as the drive assembly 56 is advanced from the retracted position to an intermediate position in the direction indicated by arrows “D” to move the tool assembly 20 from the open position to the clamped position. As illustrated, the control knob 102 is in its second position and the knife bar assembly 54 is disengaged from the drive assembly 56. Movement of the drive assembly 56 in the direction of arrow “D” causes the lower beam 76 of the working member 72 to move into engagement with the angled cam surface 68 a of the channel member 42 to pivot the cartridge assembly 38 in relation to the anvil 36 in the direction indicated by arrows “E” to the clamped position. As the distal portion of the staple cartridge 44 approaches the distal portion of the anvil 36, the locking member 39 of the anvil 36 engages the tissue guide portion 50 of the staple cartridge 44 and is deflected outwardly in the direction indicated by arrow “F” (FIG. 16) into the opening 65 of the staple cartridge 44. When the locking member 39 moves into the opening 65, the locking member 39 snaps back to its original configuration in the direction indicated by arrow “G” in FIG. 19 such that the hook portion 39 a of the locking member 39 engages an inner wall of the staple cartridge 44 to secure the distal portions of the staple cartridge 44 and the anvil 36 in relation to each other.

The locking member 39 functions to define a maximum tissue gap between the staple cartridge 44 and the anvil 36 during firing of the tool assembly 20. It is noted that when the drive assembly 56 is advanced independently of the knife bar assembly 54, the upper beam 88 of the knife bar assembly 54 does not translate through the tool assembly 20 and, thus does not define the maximum tissue gap in the area of staple formation with the working member 72 of the drive assembly 56. The locking member 39 provides this function when the tool assembly 20 is fired without the knife bar 82.

FIGS. 20 and 21 illustrate the tool assembly 20 as the drive assembly 56 is advanced from the retracted position to the advanced position in the direction indicated by arrows “H” to eject staples 62 from the tool assembly 20. As the working member 72 of the drive assembly 56 is advanced through the tool assembly 20, the working member 72 engages and advances the actuation sled 58 through the tool assembly 20. As the actuation sled 58 approaches its advanced position, the finger 100 that extends from the distal end of the actuation sled 58 engages the flexible locking member 39 and forces the locking member 39 from the opening 65 to unlock the distal portions of the anvil 36 and cartridge assembly 38. This allows the tool assembly 20 to move partially towards the open position. In embodiments, the locking member 39 includes a notch 122 to facilitate bending of the locking member 39 upon contact with the finger 100.

FIGS. 22 and 23 illustrate the drive assembly 56 as it is moved towards the advanced position engaged with the knife bar assembly 54. As discussed above, the knife bar assembly 54 can be rotated into engagement with the drive assembly 56 when the drive assembly 56 is in its fully retracted position by rotating the control knob 102 from its first position to its second position. When the drive assembly 56 is engaged with the knife bar assembly 54 and advanced in the direction indicated by arrows “J”, the knife bar assembly 54 is advanced with the drive assembly 56 in the direction indicated by arrows “J”. As the knife bar assembly 54 is advanced through the tool assembly 20, the upper beam 88 moves through the anvil channel 90 defined in the anvil 36. Since the knife bar 82 of the knife bar assembly 54 is engaged with the working member 72 of the drive assembly 56, the upper and lower beams 88 and 76 of the knife bar 82 and the working member 72, respectively, define a maximum tissue gap between the anvil 36 and the cartridge assembly 38. However, the locking member 39 is still received in the opening 65 of the staple cartridge 44 to provide additional stability to the tool assembly 20 during firing. The distally extending finger 100 of the actuation sled 58 functions as described above to release the locking member 39 from engagement with the staple cartridge 44 when the actuation sled 58 is advanced to its distal-most or advanced position.

The disclosed tool assembly 20 can be used in a cutting mode or a non-cutting mode by simply rotating the knife bar assembly 54 into and out of engagement with the drive assembly 56. The provision of the locking member 39 allows for a maximum tissue gap to be maintained between the anvil 36 and the cartridge assembly 38 when the stapling device 10 is actuated in the cutting mode or the non-cutting mode to improve the quality of staple formation. It is envisioned that the locking member 39, although shown on the anvil 36 could be incorporated onto the staple cartridge 44. It is also envisioned that the disclosed tool assembly 20 could be incorporated into a robotically controlled stapling device or include an electrically powered handle assembly.

FIG. 24 illustrates the drive assembly 56 as it is moved towards the retracted position engaged with the knife bar assembly 54. As the drive assembly 56 is retracted in the direction indicated by arrow “K”, the knife bar assembly 54 is also retracted. When the drive assembly 56 and the knife bar assembly 54 are fully retracted, the tool assembly 20 can return to the open position (FIG. 1).

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments. It is envisioned that the elements and features illustrated or described in connection with one exemplary embodiment may be combined with the elements and features of another without departing from the scope of the disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described embodiments. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A tool assembly comprising: an anvil defining an anvil channel and a knife slot communicating with the anvil channel; a cartridge assembly including a channel member and a staple cartridge, the channel member configured to receive the staple cartridge and defining a longitudinal slot, the staple cartridge supporting a plurality of staples and defining a knife slot that is aligned with the longitudinal slot; a drive assembly including a resilient beam and a working member, the working member including a first beam and a first vertical strut, the vertical strut including first engagement structure, the drive assembly movable in relation to the anvil and the cartridge assembly between advanced and retracted positions; and a knife bar assembly including a knife bar and a flexible drive member, the knife bar including a second beam and a second vertical strut, the second vertical strut supporting a knife and including second engagement structure, the knife bar assembly being selectively rotatable between first and second positions, wherein in the first position, the first and second engagement structures are coupled together such that movement of the drive assembly between the retracted and advanced positions causes corresponding movement of the knife bar assembly between the retracted and advanced positions, and in the second position, the first and second engagement structures are uncoupled such that the drive assembly is movable independently of the knife bar assembly between the retracted and advanced positions.
 2. The tool assembly of claim 1, wherein one of the anvil and the cartridge assembly includes a locking member, the locking member being positioned on a distal portion of the one of the anvil and cartridge assembly and configured to engage the other of the anvil and cartridge assembly to secure the distal portions of the anvil and the cartridge assembly together and define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.
 3. The tool assembly of claim 2, wherein the locking member includes a hook portion supported on the distal portion of the anvil and the staple cartridge defines an opening that receives the hook portion when the tool assembly is moved to a clamped position to secure the distal portion of the anvil to the distal portion of the cartridge assembly.
 4. The tool assembly of claim 1, wherein the second beam is received with the anvil channel of the anvil and the second vertical strut extends through the knife slot of the anvil when the knife bar assembly is in the first position and is advanced within the tool assembly.
 5. The tool assembly of claim 1, wherein the first engagement structure includes a first L-shaped slot and the second engagement structure includes a first L-shaped leg, the first L-shaped leg being received within the first L-shaped slot when the knife bar assembly is in the first position.
 6. The tool assembly of claim 1, wherein the first engagement structure includes a first L-shaped slot and a first L-shaped leg and the second engagement structure includes a second L-shaped leg and a second L-shaped slot, the first L-shaped leg being received within the first L-shaped slot and the second L-shaped leg received within the second L-shaped slot when the knife bar assembly is in the first position.
 7. A stapling device comprising: an elongate body having a proximal portion and a distal portion; and a tool assembly supported on the distal portion of the elongate body, the tool assembly including: an anvil defining an anvil channel and a knife slot communicating with the anvil channel; a cartridge assembly including a channel member and a staple cartridge, the channel member configured to receive the staple cartridge and defining a longitudinal slot, the staple cartridge supporting a plurality of staples and defining a knife slot that is aligned with the longitudinal slot; a drive assembly including a resilient beam and a working member, the working member including a first beam and a first vertical strut, the first vertical strut including first engagement structure, the drive assembly movable in relation to the anvil and the cartridge assembly between advanced and retracted positions; and a knife bar assembly including a knife bar and a flexible drive member, the knife bar including a second beam and a second vertical strut, the second vertical strut supporting a knife and including second engagement structure, the knife bar assembly being selectively rotatable between first and second positions, wherein in the first position, the first and second engagement structures are coupled together such that movement of the drive assembly between the retracted and advanced positions causes corresponding movement of the knife bar assembly between the retracted and advanced positions, and in the second position, the first and second engagement structures are uncoupled such that the drive assembly is movable independently of the knife bar assembly between the retracted and advanced positions.
 8. The stapling device of claim 7, further including a control knob supported on the stapling device proximally of the tool assembly, the control knob secured to the flexible drive member of the knife bar assembly and rotatable to cause rotation of the knife bar assembly between the first position and the second position.
 9. The stapling device of claim 8, wherein the control knob is supported on the elongate body at a location accessible to a clinician.
 10. The stapling device of claim 9, wherein the elongate body includes an inner housing portion that defines a cylindrical cavity that receives the control knob, wherein the control knob does not extend outwardly of an outer diameter of the elongate body.
 11. The stapling device of claim 10, wherein the control knob includes first and second protrusions and the inner housing portion of the elongate body includes at least one recess positioned to receive the first and second protrusions to retain the control knob in the first and second positions, respectively.
 12. The stapling device of claim 7, wherein one of the anvil and the cartridge assembly includes a locking member, the locking member being positioned on a distal portion of the one of the anvil and cartridge assembly and configured to engage the other of the anvil and cartridge assembly to define a maximum tissue gap between the anvil and the cartridge assembly during firing of the tool assembly.
 13. The stapling device of claim 12, wherein the locking member includes a hook portion supported on the distal portion of the anvil and the staple cartridge defines an opening that receives the hook portion when the tool assembly is moved to a clamped position to secure the distal portion of the anvil to the distal portion of the cartridge assembly.
 14. The stapling device of claim 7, wherein the second beam is received with the anvil channel of the anvil and the second vertical strut extends through the knife slot of the anvil when the knife bar assembly is in the first position and is advanced within the tool assembly.
 15. The stapling device of claim 7, wherein the first engagement structure includes a first L-shaped slot and the second engagement structure includes a first L-shaped leg, the first L-shaped leg being received within the first L-shaped slot when the knife bar assembly is in the first position.
 16. The stapling device of claim 7, wherein the first engagement structure includes a first L-shaped slot and a first L-shaped leg and the second engagement structure includes a second L-shaped leg and a second L-shaped slot, the first L-shaped leg being received within the first L-shaped slot and the second L-shaped leg received within the second L-shaped slot when the knife bar assembly is in the first position. 